The present invention relates generally to crop harvesting machines, such as mower-conditioners or windrowers, having a header floatingly connected to the frame by upper and lower links and, more particularly, to a mechanism for changing the cutting angle of the cutterbar mounted in the header while the harvesting machine is in motion harvesting standing crop.
It is well known in the art to provide a header operatively mounting a cutterbar and other harvesting apparatus, including a reel and an auger, connected to the frame of the crop harvesting machine for motion relative thereto. Generally, upper and lower links interconnecting an upper portion and a lower portion, respectively, of the header to the frame permit the header to be moved generally vertically with respect to the ground and the frame to provide a floating movement of the header to better follow undulations in the ground surface. The cutterbar is normally mounted at the forward end of the crop harvesting header to sever standing crop material and initiate the crop harvesting process. It has been found that the angle of the cutterbar relative to the ground, i.e., the cutting angle of the cutterbar, must be varied to correspond to different operating conditions to maintain optimum cutting and feeding of severed crop over the cutterbar, minimize guard and knife damage, and maintain a cutting height close to the ground.
Present crop harvesting machines provide for adjustment of the cutterbar cutting angle by varying the attachment points of the upper links and/or varying the length of the upper links themselves. Such adjustments are manually accomplished when the crop harvesting machine is stationary and prior to the usage of the machine to harvest crop. One known prior art mechanism for changing the cutterbar cutting angle includes the utilization of a turnbuckle within the upper link to change the length thereof, but manipulation of the turnbuckle must also be done while the machine is stationary. It has been found that operating conditions can vary within the same field of standing crop material and it would be inconvenient and time consuming to stop the harvesting machine to adjust the cutting angle with every change in operating condition. Yet, it is desirable for optimum efficiency to change the cutting angle to correspond to the operating condition being encountered. It would therefore be particularly desirable to provide the capability to change the cutterbar cutting angle while on-the-go.